1. Field of the Invention
This invention relates to a medical apparatus and method for occluding the flow of blood at a preselected position within a vessel of the human body, and more particularly, relates to an aneurysm embolization device for filling a high volume or wide neck aneurysm and a deployment system for releasing the embolization device within the aneurysm.
2. Description of the Prior Art
For many years physicians have been placing various devices within a blood vessel of the human body in order to treat an aneurysm by promoting thrombus formation. Such devices include balloons, coils, fiber retainers, multi-element anchors, and micropellets. Balloons are introduced into an aneurysm using a deployment catheter and then inflated within the aneurysm. The balloon prevents the flow of blood within the parent vessel from entering the aneurysm.
Another type of occluding device is an embolic coil. Embolic coils may take the form of helically wound coils, randomly wound coils, coils wound within other coils, or many other coil configurations. These coils are generally formed of metallic materials, such as platinum, gold, and tungsten, or alloys of these metals. Often times, several coils need to be placed within an aneurysm in order to occlude the flow of blood.
Furthermore, a retainer which holds at least one fiber bundle can occlude the flow of blood. The retainer can take the form of a cube, sphere, cylinder, coil, oval, or other similar shape. The thrombogenic fibers are longer than the retainer and can be made of silk, cotton, nylon, or polyurethane. These fiber bundles occlude the flow of blood in a vessel. This device is primarily used in small vessels of the vasculature.
Also, a multi-element occlusion device can stop the flow of blood in a vessel. This device has two or more elements connected by at least one metallic or nonmetallic fiber. The elements can be particles or coils with various sizes and shapes. The device is deployed with a catheter and flows downstream until the anchoring element lodges against the vessel wall. The multiple elements connected to the anchor help create deep occlusion. This device cuts off the flow of blood in a vessel and reduces the risk of continued canalization within the vessel.
Finally, micropellets are cylindrical members formed from a biocompatible foam or gel material. Several micropellets can be linked together with a carrier wire and when the micropellets are soaked in a fluid, they expand to fill an aneurysm. The swelled micropellets occlude the flow of blood and become fixed within the aneurysm.
Balloons, coils, fiber retainers, multi-element anchors, and micropellets are devices beneficial in treating aneurysms. However, the present invention is useful in treating large aneurysms or wide neck aneurysms. The present invention is an embolization device which occludes the flow of blood in an aneurysm, reduces the risk of becoming dislodged, allows blood to continue flowing through the parent vessel, and allows for retrieval or realignment.
In accordance with one aspect of the present invention, an aneurysm embolization device and deployment system is provided for use in placing the aneurysm embolization device at a preselected position within a vessel of the body. The deployment system includes a deployment catheter formed of a material which is sufficiently flexible to pass through the vasculature of the body. The proximal section of the catheter has substantially no radial expansion when fluid pressure is applied to the lumen of the catheter. The distal section of the catheter expands radially when fluid pressure is applied. The deployment system also includes a headpiece. The distal section of the headpiece is hemispherical in shape while the proximal section of the headpiece is cylindrical and is disposed within the lumen of the deployment catheter. Furthermore, the deployment system includes a central connecting member. The central connecting member is a flexible fiber which is attached at one end to the headpiece. The deployment system also includes a spherical member. The spherical member is a small diameter ball and is disposed about the central connecting member. Finally, the proximal section of the deployment catheter includes a connector. The connecter is adapted for a fluid pressure generating device and is used for applying fluid pressure to the lumen of the deployment catheter causing the distal section of the catheter to expand radially thereby releasing the headpiece and deploying the aneurysm embolization device.
In accordance with another aspect of the present invention, an aneurysm embolization device is provided for use in occluding the flow of blood at a preselected position within a vessel of the human body. The aneurysm embolization device includes a headpiece. The distal section of the headpiece is hemispherical in shape while the proximal section of the headpiece is cylindrical and is disposed within a deployment catheter. The aneurysm embolization device also includes a central connecting member. The central connecting member is a flexible fiber which is attached at one end to the headpiece. Finally, the aneurysm embolization device includes a spherical member. The spherical member is a small diameter ball and is disposed about the central connecting member.
In accordance with a similar aspect of the present invention, the headpiece and spherical member are made of a polymer or metallic material.
In accordance with a similar aspect of the present invention, the headpiece and spherical member are made of a metallic material.
In accordance with a similar aspect of the present invention, the central connecting member takes the form of a shape memory wire. After the aneurysm embolization device is deployed within the vasculature of the body, the wire tends to assume a predetermined configuration.
In accordance with another similar aspect of the present invention, the central connecting member takes the form of a stretchable fiber.
In accordance with a similar aspect of the present invention, the headpiece includes a pocket which takes the form of a concave indentation on the headpiece at a position where the central connecting member attaches to the headpiece. As a result, the central connecting member can coil up into the pocket during deployment.
In accordance with another similar aspect of the present invention, the spherical member includes a pocket which takes the form of a concave indentation on the spherical member at a position where the central connecting member attaches to the spherical member. As a result, the central connecting member can coil up into the pocket during deployment.
In accordance with a similar aspect of the present invention, the spherical member includes a plurality of filaments which are attached generally radial to the spherical member. The filaments enhance the occlusive effect of the spherical member.
In accordance with another aspect of the present invention, the spherical member includes a time-released adhesive on the periphery of the spherical member. The adhesive enhances the occlusive effect of the spherical member.
In accordance with another aspect of the present invention, the aneurysm embolization device and deployment system includes six spherical members.
In accordance with another aspect of the present invention, a method is provided for placing an aneurysm embolization device at a pre-selected position within a vessel. The method includes providing a delivery catheter having an elongated flexible tube and introducing the deliver catheter into the vasculature of the human body. The method also includes providing a deployment system having a deployment catheter. The proximal section of the catheter exhibits the characteristic of having substantially no radial expansion when fluid pressure is applied to the lumen of the catheter. The distal section of the catheter exhibits the characteristic that, when fluid pressure is applied to the lumen of the catheter the distal section of the catheter expands radially. The method further includes providing an aneurysm embolization device having a headpiece disposed within the deployment catheter. The aneurysm embolization device also includes a central connecting member which takes the form of a flexible fiber. The proximal end of the connecting member is attached to the headpiece. Finally, the embolization device includes a spherical member which takes the form of a small diameter ball. The spherical member is disposed about the central connecting member. The method further includes introducing the deployment system and the aneurysm embolization device into the delivery catheter and aligning the aneurysm embolization device with the pre-selected position within the vessel. The method finally includes applying fluid pressure to the deployment catheter causing the distal section of the deployment catheter to expand radially thereby releasing the aneurysm embolization device.
These aspects of the invention and the advantages thereof will be more clearly understood from the following description and drawings of the preferred embodiment.